This invention relates to improvements in onboard devices to aid persons in boarding and leaving passenger buses and similar vehicles. The invention is herein illustratively described by reference to the presently preferred embodiment thereof as applied to an existing type of entryway in a conventional motor bus; however, it will be recognized that the novel principles involved may be embodied in varying configurations and to different types of passenger vehicles.
There have been a number of different vehicle-mounted boarding aids for use by crippled persons who cannot ascend and descend a stairway in the normal manner. Usually employing some sort of elevator platform that can be raised and lowered between inside passenger deck level and adjacent ground level or curb level, these devices largely have pre-empted the passageway in which mounted so as to require deployment and actuation of the elevator mechanism in its regular operating cycle in order to open up and utilize the entryway if it was to be used at all for ingress and egress. Consequently such vehicles as a practical matter were also required to have a separate entryway with one or more steps for normal passengers, thereby adding to the cost and restricting the efficient utilization of the full space within the vehicle. Attempts have also been made to provide elevator mechanisms permitting dual purpose use of the same entryway, that is, with the elevator means not in use stowed in such a manner as to provide a step and/or avoid interference with normal use of an existing entryway stair. These generally have not been commercially successful, however, presumably for such reasons as undue complexity with attendant reliability problems, cost, bulkiness and/or requirements for specially designed vehicles or extensive alterations in conventional vehicles to accommodate the mechanisms.
It is a principle object of this invention to provide improved passenger vehicle dual purpose entryway combined access stairstep and elevator means overcoming the foregoing and related problems and limitations. More specifically, an object is to provide a safe, reliable and practical passenger elevator or lift mechanism for use in physical association with the normal passenger entryways of conventional motor buses and other passenger vehicles and which, when stowed between periods of use as an elevator, presents no obstruction or hindrance to the regular use of stairs in that entryway by passengers entering and leaving the vehicle on foot.
A further object hereof is to provide a stowable elevator mechanism for the described purpose compatible with passenger vehicles of conventional design, and compactly stowable beneath the passenger deck of a vehicle so as to present no entryway obstruction, no interference with operation of the entryway doors, and no downwardly projecting parts that could reduce the ground clearance beneath the vehicle. A related objective is to devise such a mechanism with base support and guide means fixed to the vehicle, and deployable mechanism and actuators therefor which, when stowed, are arranged when folded so as to lie substantially at the same level of height and to occupy a minimum horizontal spread in either breadth or width dimensions and thereby to lend the mechanism well to incorporation readily in vehicles of conventional design with comparatively few and simple changes in the entryway and adjoining below-deck structure of the vehicle frame and body.
Still another purpose relating to the reliable simplicity, compactness and versatility of the mechanism is to enable utilizing the elevator platform member when in stowed position as a step, preferably the bottom step, in the entryway stair. By so doing, there is a further reduction in the space required for stowage of the mechanism below the passenger deck and, moreover, a related reduction in the length of the extension and retraction stroke of the actuator and guide means to move the platform member outwardly for deployment and inwardly for stowage.
The invention also is concerned with achieving by a simple and reliable mechanism the necessary full range of elevating and selective lowering movements of the extended platform member both above and below the normal stowage level thereof, and in the course of such movements, maintaining the platform member steadily horizontal. Furthermore in the process of elevating the platform member to deck level the same mechanism also draws it gradually inward into abutment with the passenger deck, whereas in the reverse motion the platform member moving gradually away from the deck can be lowered gently with fluid actuator damping to any desired stopping level where it settles upon an adjacent elevated sidewalk, or in rural areas, upon a street or roadside surface at lower level. Thus wheelchair users can safely enter and leave the vehicle without other assistance using the same entryway as normal passengers by way of the usual step or stairs also occupying the entryway.
A related and more specific object is to utilize the retracted elevator platform member serving as a bottom step in the entryway as a support for steadying rail and rail post means in convenient position at either or both sides of the entryway for normal passengers to use with the elevator mechanism retracted, which rail and rail post also serve as a safety barrier and hand grab for crippled persons or persons in a wheelchair throughout their boarding and departure travel on the elevator.
These and other objects will become more fully appreciated or evident as the description of the invention in its preferred embodiment proceeds hereinbelow.